Regulation of temperature in furnaces



Lamm J. M E'WEPWOD mummow or TEMPERATURE IN FURNACES Filed ma :50 I 9 3 Shaka-sheet 1 Feb. 24, 1925. Q

J. M. HOPWOUD REGULATION OF TEMPERATURE IN FURNACES 3 Sheets-Shofl Filed Oct. 30, 1920 Ill] INVENTOR.

Feb. 24, 1925. 152mm J. M. HOPWOOD REGULATION OF TEMPERATURE IN FURNACES Filed Qot. 5Q 192 0 isneet'vsnoet INVENTOR.

' Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

JOHN M. HOPWOOD, OF PITTSBURGH, PENNSYLVANIA.

REGULATION OF TEMPERATURE IN FURNACE.

Application filed October 30, 1920. Serial No. 420,644.

To all whom it may concern.

Be it known that 1, JOHN M. Horwooo, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Regulation of Temperature in Furnaces, of which improvements the following is a specification.

The invention described herein relates to automatic means for such regulation of the feed of fuel and air for the combustion of the fuel as will ensure the maintenance of a substantially uniform temperature in furnaces, such improvements being applicable to metallurgical, boiler, and other furnaces, and has for its object the employment of mechanism controllable by and in accordance with changes of temperature in a furnace for regulatingthe operation of fuel feed means, controlling the quantity of air flowing to the furnace, and controlling the escape of products of combustion from the furnace. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification, Fig. 1 is a view partly in elevation 'and partly in section of a furnace having combined therewith means for regulating the feed of fuel and air embodying the invention claimed herein; Fig. 2 is a view partly in elevation and partly in section of a form of controlling and regulating mechanism; and Fig. 3 is a diagrammatic view illustrating an embodiment of the improvement for maintaining the article or thing being heated at a substantially constant temperature.

In the practice of the invention any suitable construction of fuel feed mechanism can be employed, as for example, the furnace being of the center feed type, a screw may be employed for feeding the fuel into and along the central trough, said screwbeing rotated by a lever 1 which is connected to the strap 4 of an eccentric 5 on the shaft 6.

In the form of apparatus shown, this shaft is rotated by an electric motor 7 but any other form or construction of motor can be employed. The terminals of the motor are connected by conductors 8 to a rheostat 9 having a controlling lever 10.

The admission of air for the support of combustion is controlled by a valve 11 in a conduit 12 and the escape of products of combustion from the stack 13 is controlled by a damper 14: operative by a. suitably arranged lever 15.

While particular forms or constructions of furnaces, fuel feed, air control, and control of the escape of products of combustion, are shown or described herein with more or less particularity, it will be understood that the invention as hereinafter more particularly described and claimed, is not limited as-regards fuel and air feed and control of products of combustion to any particular form or construction of furnace, controlling device, or fuel employed as the improvement is readily adjustable to other forms and constructions of mechanism or controlling or regulating mechanism or dif ferent forms and types of furnaces and various kinds of fuel employed.

The regulating mechanism consists of a shell or casing consisting of covers 16 and 17 secured on opposite sides of an annular shaped block 18. Between the oppositesides of this block and the respective covers are secured flexible diaphragms 19 and 20 and betw n these diaphragms is arranged a block 21. A shaft 22 is passed through this block and projects throu h slides in the annular block 18 and to t e projecting ends of this pin or shaft 22 are connected the ends of the arm of a bifurcated'lever 23, so that on the movement of the block or disc as hereinafter described, this lever will be correspondingly shifted. It Will be observed that the diaphragms 19 and 20 do not contact with the inner areas of the opposite sides of the block so that when the block is shifted, thearea of contact of one diaphragm will be increased and that of the other decreased, dependent upon the direction in which the block is shifted. This movement and corresponding change of areas of the diaphragms will continue until by reason of the increase of area of the side having the lower pressure and the decrease of the area of the opposite side, equilibrium will be established. This form of motor is described and claimed in Letters Patent No. 1,371,242 granted to John M. Hopwood May 15th 1921. The upper diaphragm is subjected to the pressure of a column of liquid maintained in a tube 24 connected at its lower end chamber of the motor and at the upper end with a basin 25. This basin is formed of such horizontal dimensions that the rise of liquid in the tube 24 due to an upward with the upper phragm 19 by changing the position of the basin along the post 26. The under chamber of this motor is connected to the end of a vertical stand pipe 27 having'its upper end open and provided at a point intermediate its ends with a branch 28 connecting with a shell 29 which as shown in Fig; 1 is arranged in the wall of the furnace so as to be subject to the temperature of the furnace and susceptible to any variations of temperature. As the mercury in the shell 29 is heated, it will expand, thereby increasing the height of the column in the pipe 27 and subjectlng the diaphragm 20 to a higher pressure. This higher pressure will cause an upward movement of the block or disc 21 thereby reducing the area of contact between the block and the diaphragm 20 and increasing the area of contact between the diaphragm 19 and the upper side of the block. The movement of the block will continue until the lower or normal pressure in the pipe 24 acting on the increased area of contact of the diaphragm 19 on theblock, counter-balances the greater pressure acting through the reduced area of contact of the diaphragm 20 on the lower side of the block, whereupon the movement of the disc will cease. While any suitable means or I construction of mechanism may be employed for utilizing the movement imparted to the lever 23 by the above described movement of the block, it is preferred to employ the construction shown herein. In this construction the lever 23 is connected by a IOd 30 to a pivotally mounted frame 31. In this frame is pivotally mounted a bell crank lever having its arm 32 connected by a stem 33 to the movable member of a pilot valve mechanism 34, said valve mechanism controlling the flow of fluid pressure to and from both ends of the cylinder 35, the piston of said cylinder being connected by the piston rod 36 to the frame 37. The arm 38 of the bell crank lever is connected by a link 39 to a pivotally mounted post 40 havmg a shoe 41 pivotally mounted in its upper end. A bar 42 is adjustably secured to .the frame 37 so that it may be shifted to any desired angle to the axis of the cyl nder 35. This bar is adapted to slide along the shoe 41 as the frame is raised or lowered. In the operation of the device, when the frame 31 has been shifted by a movement of the block 21, the movable member of the valve mechanism 34 is shifted to permit fluid pressure to flow to one end of the cylinder and to escape from the opposite end, thereby causing a movement of the post and frame 37. As .the frame 37 moves up it will cause the angularly arranged rod 42 to slide through the shoe 41 and thereby shift the pivotally mounted post 40. By the movement of this post the bell crank lever is shifted and thereby moving the movable member of the valve mechanism in a direction contrary to that effected by a movement of the frame and checking the flow of fluid pressure to and from the cylinder. It will be readily understood that by shifting the angular position of the rod 42 the range of movement of the piston of the cylinder can be controlled as desred.

This frame 37 is connected by a rope 47 to the operating arm 10 of the rheostat 9 and also by a rope 45 passed around suitable guide pulleys to the operating arm of the valve 12 contr olling the flow of air for combustion to the furnace. A damper 14 is made of such a weight that when free to move it will drop down onto the end of the stack thereby stopping the flow of gases from the furnace. Its opening movement is effected by a movement of the frame 37 through the rope 46 connected to the operat ing lever 15.

By making the vertical stand pipe of such a'size that its capacity is small relative to the capacity of the shell 29, a small change in temperature in the furnace will effect a substantial change in the height of the mercury in the stand pipe and thereby cause a corresponding shifting of the block 21 of the motor and a corresponding adjustmentof the mechanisms controlling the combustion conditions 'as hereinbefore described.

Until the liquid in the shell 29 is subjected to heat the pressure exerted on the diaphragm 19 will be greater than that exerted by the column in the pipe 27 on the diawill e in its lowest position. The mechanisms interposed between the block and the fuel and air feeding devices and the stack damper are so adjusted as to promote combustion when the block is in its lowest position. As the temperature due to combustion in the furnace increases, the liquid in the shell 29 will expand thereby-increasing the height of the liquid column operative on the diaphragm 20. The progressive increase of temperature up to the normal or desired temperature on the underside of the block, will cause a progressive upward movement of the block and a corresponding adjustment of the feedof fuel and the feed of air and the position of the stack damper until the desired temperature has been attained, when the rate of combustion will be checked.

In some cases the maintenance of uniformity of temperature in the furnace is not the prime essential, but the attainment and maintenance of the thing or material being heated at a desired or predetermined temperature, as for example the heating of oil for distillation. In such cases the shell 29 which is connected to the stand 27 is placed in the boiler of the still, as shown in Fig. 3, or in such relation to any other object being heated that it will have the temerature of that object or a temperature earing a definite relation to the temperature of that of the object.

In the embodiment of the improvement shown in Fig. 3 the controlling mechanism operative by changes of temperature in the boiler, is indicated at A, and the motor mechanism whereby the feed of fuel and air and the discharge of products of combustion are regulated, is indicated at B. The controlling and motor mechanisms are preferably similar to those shown in Figs 1 and 2 and hereinbefore described, except that the fuel feeding mechanism is operative by fluid pressure and hence in place of a rheostat controlling an electric motor, a valve mechanism indicated at 4:8 is employed for controlling the flow of fluid pressure to the stoking mechanism and has its operating lever 10 connected by the rope 47 to the frame 37 and the valve 11 controlling the flow of air for combustion is also operative as shown by the frame. The damper 14 is also connected to the frame by a rope 46.

It will be readily understood by those skilled in the art that by adjusting the height of the column operative on the diaphragm 19 the maximum temperature desired can be varied and maintained. at such point until the position of the basin 25 is shifted. This feature is especially advantageous in distilling oils and in other operations where it is necessary or desirable to maintain a certain temperature until the light constituents are driven off and then increase the temperature and-hold it at such points until the other constituents are driven off.

I claim herein as my invention:

1. The method herein described of controlling the temperature of a furnace which consists in applying pressures of liquid columns to opposite sides of the movable member, the pressure by one column being yielding but substantially constant, varying the height of the other column by and in accordance with changes of temperature in the furnace and thereby shifting said member and utilizing the movements of this memher for controlling one of the operations im volved in generating heat in the furnace.

2. In an apparatus for regulating temperature in the furnace, the combination of a. movable block, diaphragms contacting with opposite sides of the block, liquid columns for applying oppositely acting pressures to said diaphragms, the height of one of the columns being substantially constant and the height of the other column being variable by heat, and means for utilizing the movement of the block due to a change in the height of said column to regulate an operation involved in the generation of heat in the furnace.

3. In an apparatus for regulating temperature in the furnace, the combination of a movable block, diaphragms contacting with opposite sides of the block, liquid columns for applying oppositely acting pressures to said diaphragms, the height of one column being substantially constant and the height of the other variable by heat, means for adjusting the height of the first column to change the temperature to be maintained in the furnace, and means forutilizing the movement of the block due to a change of height of the second column due to change of heat in the furnace to regulate an operation involved in the generation of heat in the furnace.

4. An apparatus for controlling the rate of combustion of fuel in a furnace having in combination a movable block, a liquid column for applying a substantially constant pressure to one side of the block, a second liquid column for applying to said block an oppositely acting pressure adapted to be varied by changes in temperature generated by combustion of fuel in a furnace, a. motor having operative movements pro portional to movements of the block due to changes of temperature in the furnace and controlled by the block and means operative by the-motor for regulating the rate ofcombustion in the furnace.

5. A furnace in combination with means for feeding fuel to the furnace, a. movable bloclga liquid column for applying a substantially constant pressure to said block, a second liquid column for applying to said block oppositely acting pressures adapted to be varied by changes in temperature generated by combustion of fuel in the furnace,

a motor having operative movements proportional to movements of the block due to changes of temperature in the furnace and controlled by the block and connections from the motor to the fuel feeding means.

6. A furnace in combination with means for feeding air and fuel to the furnace, a movable block, a liquid column for applying a substantially constant pressure to said block, a second liquid column for applying the furnace and controlled by the block and connections from the motor to the fuel and air feeding means.

7 A furnace in combination with means for feeding fuel tothe furnace, means for feeding air to the furnace, and means for adjusting the stack damper of the furnace, a movable block, a liquid column for applying a substantially constant pressure to said block, a second liquid column for applying to said block an oppositely acting pressure adapted to be varied by changes in the temperature generated by combustion of fuel in the furnace, a motor having operative movements proportional to the movements of the block due to changes of temperature in the furnace and controlled by the block and connections from the motor to the several means employed for feeding fuel and air and for adjusting the stack damper.

S. The combination of a furnace, a movable member or block, means for applying to one side of said block the pressure of a liquid column substantially constant in height, means for applying to the opposite side of said block the pressure of a column of liquid having a substantial coefficient of expansion on changes of temperature, meansfor varying the height of said column by and in accordance with changes of temperature in the furnace and means controlled by said block for varying the rate of combustion Within the furnace.

9. The combination of a furnace, a movable block, means for applying to one side of said block the pressure of a liquid column substantially constant in height, means for applying to the opposite side of said block the pressure of a column of liquid having a substantial coeflicient of expansion on changes of temperature, means for varying the height of said column by and in accordance with changes of temperature due to changes in rate of combustion in the furnace and means controlled by said block for varying the rate of combustion in the furnace.

101 The combination of a furnace, a movable block, means for applying to one side of said block the pressure of a liquid column of a height substantially constant for predetermined temperature, means for adjusting the height of said column when a change of temperature in the furnace is desired, means for applying to the opposite side of said blockthe pressure of a column of liquid having a substantial coefiicient of expansion on changes of temperature, means for varying the height of said column by and in accordance with changes of temperature due to changes of rate in combustion and means controlled by said block for varying the rate of combustion.

In testimony whereof, I have hereunto set my hand.

JOHN M. HOPWOOD. 

